LIST OF ILLUSTRATIONS XXlll 



FIG. PAGE 



326. Bdellostoma stouti (Californian hag), enveloped in sheath of 



mucus — after Bashford Dean .... 579 



327. The lamprey {Petromyzon marinus) .... 580 



328. Longitudinal vertical section of anterior end of larval 



lamprey ....... 583 



329. Restored skeleton of Palceospondylus gunni — after Traquair 585 



330. Pterichthys milleri. Lateral view — restored by Traquair . 586 



331. Diagram of the placoid scale of an Elasmobranch fish . 590 



332. Diagram of the " soft " scales of a Bony Fish . . -591 



333. Under surface of skull and arches of skate — after W. K. 



Parker ....... 592 



334. Side view of skate's skull — after W. K. Parker . . 593 

 333. Skeleton of skate — from a preparation . . -594 



336. Dissection of nerves of skate ..... 596 



337. Side view of chief cranial nerves of Elasmobranchs — 



slightly modified from Cossar Ewart . . . 600 



338. Spiral valve of skate — after T. J. Parker . . . 601 



339. Heart and adjacent vessels of skate — in part after Monro . 602 



340. Upper part of the dorsal aorta in the skate — after Monro . 603 



341. Urinogenital organs of male skate .... 604 



342. Urinogenital organs of female skate — in part after Monro . 605 



343. Elasmobranch development — after Balfour . . . 606 



344. Embryo dogfish in egg-case ("mermaid's purse") which 



has been cut open to show contents . . . 608 



345. External features of Acanthias vulgaris . . . 610 



346. Acanthias vulgaris. Longitudinal section showing organs . 611 



347. Side view of brain of Acanthias vulgaris — after Purser . 612 



348. Dorsal view of brain ol Acanthias vulgaris — after Purser . 613 



349. Arterial system of Acanthias — after O'Donoghue . . 614 



350. The haddock ....... 616 



351. External characters of a Teleostean — a carp {Cyprinus 



carpio) — after Leunis . . . . .617 



352. Lines of growth on salmon's scale — from J. Arthur Hutton . 6x8 



353. Diagram of the zigzag myotomes in a fish . . . 6x8 



354. Caudal vertebra of haddock ..... 6x9 



355. Disarticulated skull of cod ..... 620 



356. Pectoral girdle and fin of cod . . . . .621 



357. Section of a Teleostean gill ..... 622 



358. Diagram of Teleostean circulation — after Nuhn . . 624 



359. The early development of the salmon . . . 625 



360. Development of eel — after Schmidt .... 629 



361. Young skate — from Beard ..... 633 



